Canon EOS 1D Mark III User Guide - Page 57

• 2 UD lens elements (G12 and G15) minimize lateral chromatic aberration (a wide angle lens design problem) to produce superb image quality with excellent resolution and contrast and little or no color bleed around the outline of the subject • Lens disposition and coatings optimized to minimize the ghosting and flare that tend to occur when the lens is used with a digital camera • High resistance to dust and water droplets • Circular aperture produces beautiful out-of-focus images • Internal focusing (some elements of the second group, G5 to G7, move for focusing), ring USM, high-speed CPU and new AF algorithms for fast and quiet autofocusing • Front element does not rotate during focusing and zooming (convenient with polarizer use) • Manual focusing enabled even during the AF mode (full-time mechanical manual focus) • Optical system constructed using only lead-free glass • Uses new EW-88 petal-shaped lens hood • Slightly larger than previous lens: filter diameter 82mm, was 77mm; length 111.6mm, was 103mm; weight 635g, was 600g X. SOFTWARE PACKAGE, COMPATIBILITY AND ACCESSORIES 57